[dragontamer]

Fair. It's not like GPUs are entirely SIMD (and as I said in a sibling post, I agree that GPUs have substantial traditional threads involved).

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But let's zoom into Raytracing for a minute. Intel's Raytrace (and indeed, the DirectX model of Raytracing) is for Ray Dispatches to be consolidated in rather intricate ways.

Intel will literally move the stack between SIMD lanes, consolidating rays into shared misses and shared hits (to minimize branch divergence).

There's some new techniques being presented here in today's SIMD models that cannot easily be described by the traditional threading models.